Fractured reservoir boundary conditions are crucial to numerical study on reservoir simulation and performance prediction of an enhanced geothermal system (EGS) but have received little attention in previous studies. We established an integrated model involving fractured reservoir and Double-flash geothermal power plant to compare heat extraction and power generation of the EGS under "recharge" and "no-flow" boundary conditions based on geothermal characteristics of Gonghe Basin, China. The "recharge" boundary conditions allow fluxes of mass and heat to cross reservoir boundaries, whereas the "no-flow" disallow such fluxes. The results show that the heat extraction potential around the periphery of the reservoir is overlooked under "no-flow" boundary conditions. Moreover, the fluxes of mass and heat across the reservoir boundaries exert limited influence on heat extraction process in initial stage, but they affect the process significantly in later stage. Additionally, compared with the EGS under "no-flow" boundary conditions, that under the "recharge" has a longer lifespan of 20%, and produces 8% more electricity power. It is also found the EGS maintains high-level power generation performance in the initial period under both boundary conditions, while the electricity output and thermal efficiency decrease significantly in the following stage. (C) 2019 Elsevier Ltd. All rights reserved.